/Engine/Source/Runtime/Engine/Classes/Engine/Texture.h
Initialize the source data with the given size, number of mips, and format.
void InitWithCompressedSourceData ( int32 NewSizeX, int32 NewSizeY, int32 NewNumMips, ETextureSourceFormat NewFormat, const TArrayView64< uint8 > NewSourceData, ETextureSourceCompressionFormat NewSourceFormat )